.OTC File Extension

Chart template created by programs that implement OASIS's OpenDocument standard; stores the default setting and layout information for a chart and may specify the dimensions, plot area, and axis information; used to create multiple .ODC files with the same look and feel.

ODC files are XML-based, similarly to other formats in the OpenDocument standard. They are stored as compressed Zip archives, which may include multiple XML files and other assets.

NOTE: OpenOffice, which was previously StarOffice, is one of the most widely-known programs that uses OTC files.